Field of the Invention
The invention relates to an electric part to be soldered to a metal pad mounted on a printed circuit board, and further to a method of fabricating the same.
Description of the Related Art
There is known an electric connector to be mounted on a metal pad formed on a printed circuit board and made of a thin metal sheet. The electric connector generally includes a connector terminal to be electrically connected to another electric connector, or an electric part called a hold-down for fixing a housing onto a printed circuit board. The connector terminal or the hold-down (hereinafter, simply called an “electric part”) is soldered to a metal pad to thereby fix the electric connector onto the printed circuit board.
An example of such an electric part is suggested in Japanese Patent Application Publication No. 2012-138183.
As illustrated in FIG. 11A, a terminal 100 suggested in the Publication includes a lead 101 connected to a connector 102 of a carrier. Both the lead 101 and the connector 102 are plated with tin to thereby form a thin notch 104 between the lead 101 and the connector 102. As illustrated in FIGS. 11B and 11C, the notch 104 is cut by means of a cutter 103, resulting in that there are formed fillets 105 comprised of portions of the notch 104, as illustrated in FIG. 11D.
The upwardly bending fillets 105 ensure that an area of a tin plating layer to which solder is fixed can be increased, and thus, there can be formed large solder fillets between the fillets 105 and a metal pad when the terminal 100 is soldered onto the metal pad.
If a metal plate plated at opposite surfaces thereof were simply cut, a non-plated material (a mother material) is exposed at a surface along which the metal plate was cut. A non-plated surface has low solder wettability. The fillets 105 are formed by cutting the notch 104 by means of the cutter 103 in the terminal 100 illustrated in FIGS. 11A to 11D. Thus, the notch 104 is stretched to be thin, and hence, the fillets 105 have a plated surface.
However, when the notch 104 is cut for forming the fillets 105, the notch 104 may be broken before the notch 104 is stretched to be thin. Thus, it is quite difficult to ensure an area of a tin-plated layer to be large merely by cutting the notch 104 to thereby stretch the notch 104 to be thin.
A peel resistance for an electric part to be peeled from a metal pad is dependent on a size of an area by which the electric part is soldered to the metal pad. Accordingly, it is necessary to make the area larger for the purpose of increasing the peel resistance. By increasing the peel resistance, the electric part can have an enhanced peel resistance to oscillation and/or impact, and further, the electric part can have a strength in such a case that a cable to which an electric connector is connected is pulled, ensuring enhancement in electrical connection between the electric part and a metal pad.